ATLLAS

ATLLAS1 Mach 3 vehicle concept

ATLLAS1 Mach 3 vehicle concept

ATLLAS1 Mach 6 vehicle propellant tank integration

DLR-SART contribution in ATLLAS studies

The ATLLAS studies are running in parallel to the propulsion related LAPCAT studies. In contrast to the latter ATLLAS is focused on research on structures and thermal protection systems for high speed vehicles. The project objective is defined as:

"… to identify and assess advanced lightweight materials which can withstand ultra high temperatures and heat fluxes, enabling flight at speeds above Mach 3. At these high speeds, classical materials used for airframes and propulsion units are not longer viable and need to be replaced by high-temperature, lightweight materials, with active cooling of some parts.”

In ATLLAS1 two reference vehicles for intercontinental passenger transport have been defined with a Mach 3 (ATLLAS-M3) and a Mach 6 (ATLLAS-M6) concept. DLR-SART has been responsible for vehicle mass estimations, definition of the propellant tanks and CAD model generation. The propellant tank design significantly impacts the total vehicle layout since high speed vehicle concepts typically have to store the propellant within the fuselage. This is complicated due to fact that the propellant mass fraction may be significantly higher compared to today’s subsonic passenger aircraft.

For the Mach 6 vehicle DLR-SART also performed propulsion system studies and trajectory simulations. Designing the propulsion system for a hypersonic aircraft is a demanding task since propulsion and fuselage often have to be highly integrated.

The ATLLAS Mach 6 reference vehicle is based on the US Hycat 1a concept. The propellant tank integration has been a major issue since the propellant occupies most of the fuselage volume. During flight center of gravity shifting due to propellant consumption poses significant challenges for vehicle trimming. This may have a significant impact on propellant tank design and integration.

In ATLLAS1 an optimal cruising Mach number was found around Mach 5-6. Thus, the current ATLLAS2 study focuses on a Mach 5-6 vehicle. DLR-SART is involved in preliminary structural design and mass estimations. Furthermore, stochastic multi-disciplinary design improvements and analyses will be performed.